Apparatus for lifting fluid



Feb 2,5, 1947-' G. L. THOMPSON ETAL 2,416,359

APPARATUS FOR LIFTING FLUID Filed Jan. 17, 1945 6 Sheets-Sheet l x. HH.,

VEN TORS PSU/V Feb. 25,l 1947. V s. L, THoMPsoN ETAL 2,416,359

'APPARATUS FOR LIFTING' FLUID lFiled dan. 17, 1945 v s Smets-sheet 2 s,a f y Inf l E l i: ffy JNVEN roles f l' GEORGE Yfonpso/v By [fo A.C22/45,4

Feb. 25, 1947. G. 1.. THOMPSON Erm. 2,416,359

' YAPPARATUS FOR LIFTING FLUID Filed Jan". 17, 1945 sheets-Sheet 3 AW\\\\\\\\\\\\E=i M .4 Uw www w M Arrae/vfr Feb. 25, 1947. G. L. THoMPsoNErAL I APPARATUS FOR LIFTING FLUID 6 Sheets-Sheet 4 'Filed Jan. 17., 1945 l JNVENToRs ko/P65 Tlf/amaro Feb. 25; 1947.

FiledJan. 17, 1945 G. L. THoMPsoN ET'AL APPARATUS FOR LIF-TING FLUID 6Sheets-Sheet v5 IN VEN TORS 650,665 YP/OMAsa/v ATTOEA/EY Feb. 25, 1947.v

G.- L. THOMPSON ETAL APPARATUS FOR LIFTING FLUID Filed Jan. 17, 1945 6Sheets-Sheet 6 GfofaE Hoff/250A( B Z50 A. C21/f4 A TTOPNY Patented Feb.A25, 1947 NITED STATES PATENT yorti-cli:-`

APPARATUS Fon LIF'rmGFLUm George L. Thompson and Leo A, Cejka,

Avenal, Calif.

Application January 17, 1945, serial No. 573,236

This invention relates, generally, to apparatus for handling or liftingfluid and which can be used to advantage in lifting fluid from wells,and particularly from deep wells. `It is a general object of ourinvention to provide an improved, simplified, and highly efficientmechanism or apparatus of the character referred to.

In removing uids from wells, or the like, it has been common practice toemploy pumps located in the wells to be submerged in the fluids therein,which pumps have been operatedr through strings of sucker rods by meansof pump jacks, or like mechanisms, located at the heads of the wells. Insuch'cases the pumps and pump jacks have had no particular cooperativelrelationship except that the `pump jacks serve to reciprocate the rodswhich, in turn, in a gen- -eral way, operate the plungers of the pumps,

not been generally satisfactory, but rather has been wasteful of gas andundependable in action.

It is a general object of our present invention to provide a unitary orcomposite apparatus for lifting fluids from great depths, for instancefrom deep wells, by means of pressure fluid or high pressure gas, andwhich involves a definite cooperative relationship between the partslocated in the well and those operating at the head of the well, to theend that we obtain high operative efficiency, or effective conservationof the power medium, and also improved well production.

The mechanism or apparatus that we have provided by our presentinvention involves a pressure fluid displacement type working unit to be455 tending into the well to handle the well liquids and to operate thesaid unit and gas control, a fluid pressure operated actuating means atthe top of the well for operating the flow string or tubing conductingfluids from the well, and a con- 51 Claims. (Cl. 103--231) such-aggregations of 20 gas .control through the flow stringso thatthe'action vof the equipment in the well is directly coordinated with thatof the surface equipment so the entire pumping operation is carried outsmoothly, without shock, and in a highly efficient manner. With theapparatus that we have -provided the fluid issues from the well in asubstantially steady stream and not intermittently or in slugs, as isthe case when using most gas lifts or methods, employing pressure fluidas an actuating medium. In carrying out the broader principles ofoui-"invention we may employ various mediums or fluids under pressure,which we will term pressure fluidv as 'the working medium;

however, in practice and particularly when lifting fluids from deepwells, we employ gas at high pressures as the working medium and,therefore, it may be said that the invention relates to that generalclass commonly referred to as'gas lifts.

So-called gas lifts that have been proposed for l vhandling well fluidshave been used with limited success. in a few limited situations. Gaslifts generally involve complicated or delicate valves.-

or intricate controls which give considerable dimculty under actualworking conditions, and, in most cases where they work at all, they arevery ineilicient or wasteful of gas. We recognize that various pumpactuating mechanisms also have been provided and 'used for working orhandling pumps of various kinds, such mechanisms being known, generally,as pump Jacks. Such mechanisms are merely reciprocators designed tostroke f or reciprocate a string of sucker rods vor tubing to work apump plungex-,and as a general rule any pump jack will operate any wellpump within its limited range of use'.

We have found that a working mechanism in a well handling pressure fluidhas certain highly advantageous features. have very few simple,dependable parts, and vitis practical to manufacture. However,` suchstructure's have certain peculiarities which make them more or lessineiilcient when operated by the conventional type of pump jack. Withthe simple gas displacement type device when the gas is introduced intothe displacement unit in the well to displace well fluid therefrom thereis a very marked and sudden release of' pressure from the operatingstring of tubing through which the flow is handled and the pump isoperated. The s udden change of pressure occurring when the gas isintroduced into the displacement vunit results in a shock upon theoperating string and this trol for the actuating means connected withthe ShQQk is communicated to the operating mecha- For instance, lit maynism. Further, sudden stopping of the actuating mechanism at the topofthe well at the ends` of its stroke also causes shocks that arecommunicated vto the operating string in the well.

The shocks imparted to the operating string present very seriousoperating problems that are not satisfactorily met by the ordinaryoperating efficient operation of a pressure fluid apparatus it is notmerely a matter of having an operating mechanism or pump jack that willreciprocate the flow handling string without shock, but that when thepump is working at substantial depths it is necessary to employ adensity control regulator at the unit in the well, and further, that for.y high efficiency the actuating mechanism must be directly coordinatedwith the gas control and the displacement units located in the well.A

'Ihe operation of a mechanism deep inawell, and particularlytheoperation of a mechanism involving reciprocating parts and utilizing gas.pressure in the course of operation, involves several serious problems,one of which isthe maintenancey of the proper relationship between the Yparts under varying conditions. In the case of a mechanism utilizing gasunder pressure to displace fluid at the bottom of the well and having areciprocating valve controlling the gas and operated byqa mechanism atthe top of the well,y ythere is commonly a working or movement of thepump element intended to be stationary due to stretch, changingpressures or loads, and changes in temperature. Checking of the movementof the element intended to be stationary is beneflcial but is not alonea fully practical solution.

Gas used for operation in most cases varies widely in temperature, asfor instance, between day and night, or under varying field conditions,so 'if the one element of theA well mechanism or unit is fixed at itsupper end only then expansion or contraction of the other element, whichis free to move, may cause it to move so that the relationship of partsis seriously disturbed.

i It is lan object of this invention to provide adeep Well mechanism orunit utilizing high pressure gas to displace4 well fluid at the bottomof the well, and in which the so-called fixed or stationary element ofthe unit is anchored or fixed at a point deep in the well s o that it ispractically free from movement andV thus establishes a position from orwith relation to which the other parts, including the actuating unit atthe top of the well, can be setand operated. By our present invention weeliminate the disadvantages of having the entire well unit or mechanismsubject to .working or shifting in the well 'and we make possiblefeatures that will be hereinafter set forth.

variations that would otherwise complicate and ,materially detract. fromthe action of the apparatus.

A general object of our present invention is to provide a combined orcoordinated vassembly of elements including a pressure fluiddisplacement unit located in the well itself, a liquid operated pumpactuator located at the head of the well,

and a control system for the actuator directly coi ordinated with theaction of the displacement unit itself. We effect the desiredcoordination through the operating string whichis also employed toconduct uid from the well.

' Another object of our invention is to provide a highly eflicient andpractical combination of pressure uid displacement well unit operated bya tubular ow string, a. iiuid pressure actuated pump operator at the topof the well energized by gas under pressure, and means in the flowstring controlling the specific gravity of the fluid being lifted. allin a closed circuit so that there is no waste of gas or back pressure onthe well formation. h y

Another object of our invention is to provide for effective anddependable lubrication from the top of the well of working parts of themechanism in the well. In practice gas usually available for use inapparatus such as we provide is dry gas, and regardless of the gas beingused the valve surfaces in the well are blown or wiped clean and dry ateach stroke of the actuating piston. Need of lubrication is particularlyimportant in anarrangement or structure such as we have provided,

.which is, in effect, a closed circuit. We have overcome the difficultyreferred to by providing for thorough and continuous lubrication of theworking parts by apparatus at the top of the well where it can be easilyand conveniently serviced. In the preferred form of the invention thelubrication is synchronized with the action of the entire apparatus sothat continuous and adequate lubrication is assured whenever theapparatus t is operating.

Another object of our invention is to provide a safety control inconnection with the supply of actuating fluid for the unit Vat the topof the well, which fluid is held'under pressure by. gas,

fso that gas cannot reach the'unit to cause oper-- ation that mightcause injury to the parts or equipment connected thereto. If gas shouldget into the actuating unit it might cause serious i injury to either orboth of the tubings employed provide va cushioning means in theactuating unit.

at .the top of the well to eliminate shock or hammer at the surfaceparts and, more'important, to

Another object of our invention is to. provide an assembly including adisplacement unit of the general character referred to having ananchored stationary element that cannot move and an actuating unit atthe-top of the well with a range of action or freedom of `movement whichcornpensates for variations which are at a maximum because thestationary element is fixed. By providing for overtravel orover-stroking of the actuating unit we are able' to absorb Q1'neutralize eliminate shock of the inner tubing that carries unitutilizingl fluid supplied to operate the unit as` a medium for checkingthe movement of the reciprocating parts at the lower end of the strokeVso that hammer or sudden jar is eliminated.

Another object of the invention is to provide a unit at the top of thewell. combining an actuating mechanism and a iiow connectionand-provision for adjustment of the mechanism bodily to synchronize itto the parts in the well so that the ow connection is not disturbed andneeds nf. special attention lwhen the unit is adjusted. In accordancewith the preferred form of our invention the ow line has a sectionarranged coaxially with the actuating unit or mechanism and that sectionhas a slip joint which operates when the actuating unit is adjusted.-

Another' object of the invention is' to provide apparatus such as wehave referred tofin which there is a stop in a fixed. position in thestationary element of the displacement unit in the well to be engaged bythe movable element. The

stop is in a ydefinite known spaced relation toof high'pressure gasunder control of a valve and by a density control device in conjunctionwith the parts just named, which operates to introduce gas into thedisplaced fluid to lower its specific gravity and to keep its specific.gravity down to a point where the operating medium or high pressure gaswill effectively operate to displace the well uidup through thedischarge string provided for conducting the well fluid to the surface..

It is another object of our invention to provide apparatus of thegeneral character referred to wherein the parts or equipment located inthe well establish what we will term a closed system keeping the highpressure operating gas entirely away from the well or earth formation,so that no back pressure is built up or established in the well, butrather the well is allowed to flow naturally or freely and thus toproduce in a most efllcient manner.

In well apparatus ofthe general characterv that we have vreferred to,and where'there is an inner tubing, through which f the well fluid isflowed out of the Well and an outer tubing through which gas underpressure is introduced into the well to the bottom or lower regionsthereof, to effect displacement of the well fluid, initiation ofoperation may be impossible if there is a substantial level of liquidstanding in the inner tubing.

It is a general object of our present invention to provide for theremoval of liquid from the inner tubing in order to initiate operationof the apparatus. By our invention we provide one introduced into theouter tubing.

There are numerous other objects and features of our invention that willbe apparent and fully understood from the following detailedvdescription of a typical preferred form and application of theinvention, throughout which descripf tion reference is made to theAaccompanying drawings, in which:

Fig. l is a diagrammatic or schematic illustral 6 tion of the generalapparatus of the present invention showing a form of the inventionwherein highy pressure gas from a suitable source is utilized astheprime mover for the entire operation, the parts which occur in the wellbeing shown broken and arranged side by side rather than in line, asthey actually occur. Fig. 2 is an enlarged vertical detailed sectionalview of the actuating unit provided by our invention for operation atthe head of the well to reciprocate the flow string which'extends intothe well to actuate the gas control at the displacement unit. Fig. 3 isan enlarged longitudinal detailed sectional view of the three-way pilotvalve employed in the control system, being the element of the controlsystem coupling the reciprocating element operating in the well with theworking part of the control system of the actuating unit. Fig. 4 is anenlarged, detailed, sectional view of the density control regulatoremployed at the mechanism inthe well or at the lower end of theYoperating string which conducts the well fluid from the displacementunit at the bottom `ofthe well to the surface of the well. Fig. 5 is anenlarged, detailed, sectional view of one of the unloaderf valves thatmay be used in the operatingstring for starting the operation. Fig. 6 isan enlarged, longitudinal,

detailed, sectional view of parts in the well, showing in particular thegeneral location or application of the density control regulator andalso the gas control provided for the displacement unit and showing theupper end portion of the displacement unit itself. Fig. 'l is a viewsimilar to Fig, 6 showing the lower end-portion of the displacementunit. Fig. 8 vis a detailed transverse sectional view taken as`indicated by line 8-8 on Fig. 6. Fig. 9 is a longitudinal,`detailed,'trans verse sectional vview ofthe top valve of thedisplacement unit. Fi-g. 10 is a detailed, transverse, sectional viewtaken as indicated .by line IU--ill Von Fig. 9. Fig. 11 isa verticaldetailed sectional view of the bottomlvalveemployed in the displacementunit showing also the stop provided in the stationary element of thedisplacement unit. Fig. l2 is a transverse, sectional view taken on lineli2--l2 of Fig. 11. Fig; 13 is a vertical, de-

tailed, sectional view of the vent valve provided in the displacementunit. Fig. 14 is a viewshowing the manner in which the stationary tubeis anchored in the well. Fig. 15 is a diagrammatic view illustrating theintermitter and its relationship to the inlet and exhaust valves.

The apparatus that we have provided by our present invention is useful,generally, for lifting fluid and it is particularly useful in liftingfluid from deep oil wells. The apparatus canbe operated in single units,that is, ona single or individuai well, or a number of units c-an becombined so that they operate in a system or circuit using a singlesource of pressure fluid, preferably gas. For purpose of example we willdescribe a single or individual unit, it being understood that we do notthereby wish 'to limit ourselvesto use of the invention in thisparticular manner.`

be carried out in connection with wells of various constructions orunder varying field `conditions, in which case variations will be 'madetomeet the conditions encountered. In the drawings we illustrate atypical or simple well arrangement and we show the apparatus employed byour invention in connection with a simple cased well such as is commonlyencountered in practice.

In thedrawings, and in particular in -Fig. 1 of the drawings, we show awell bore W carry- It v is also to vbe understood that the invention cana common form oi' well casing I0.' The casing extends downwardly intothe well W from a suitable casing head II provided at the surface otherelements such as the outer tubing vand other parts that will behereinafter described. In the preferred form of the invention we employthe casing head of the well as a base or mounting for our actuatingunit. When thus employing the casing head of the well we employ v I Thedisplacement unit A a form of head that is adaptable to take the nipeple of a landing flanger I 2. Theange I2 carries flange 41a of thecylinder D and supports the adjusting posts and'passes the piston rod,all as will appear from the following description.

1In carrying out our invention we equip the well, that lis, the casedwell that we have just described, with a xed or outer tubing I3. The

tubing I3 is landed in the head II to depend therefrom downwardlythrough the casing I0 and it extends down in the' casing to the bottomof the well or to the point where the iluid is to be takenfrom the well,which point will be referred to as the bottom of the well, although insome cases this may not be literally true.

Q Our present invention provides, in combination with the partsorelements hereinabove described, a working string or tube that we willterm the flow string I6, a displacement unit A, a gas control B at theunit A for controlling the actuating fluid, or high pressure gas, adensity control regulator C immediately above the displacement unitconnecting the space between the ilow string I8 and tubing I3 with theinterior of the ilow string I6, one or morefunloading valves G in saidow is carried at the desired location in the well or within the wellcasing III by means of the tubing I3 and the flow string I6, theconnection between these elementsand the displacement unit being madethrough the gas lcontrol B. vIn accordance with our invention thedisplacementunit A utilizes pressure iluid, pref-4 erably high pressurelgas introduced through the annulus I1 under control of the gas controlB, so that it displaces well fluid that has enteredl the unit. It may besaid that the displacement unit operates to move or displace the wellfluid by pneumatic action, the word pneumatic" in such ca se being usedbroadly enough to include not only air but also gas. Itis to beunderstood that in carrying out some phases of our invention a mediumother than gas may be used; for instance there may be cases where' aliquid can be used. Because of thisvwedo not use the terms gas" `or4pneumatic in a limited'sense but broadly,

and we mean to include liquids where they are usable within the -scopeof our invention.

The xed tubing I3 is an elongate tubular element or string of tubingsuch as is commonly string, an actuating unit D at the head of the lwell for working the liow string so it operates'the gas control, and acontrol system E for operating and controlling the actuating unit.

. i The now string is servesas the conduit or pipe for conducting theiluid from the unit A to the 'surface or head of the well, and also asthe means for actuating' the control B. The fluid `that is thus vhandledis a mixture of well fluid land actuating gasmlIn practice the ow stringI6 is a string of tubing, or the like, of the type known in I the art asmacaroni.

The now string I6 is smaller in diameter than the tubing I3 so thatthere is an annular space employed in wells when they are to be pumped.

'I'he upper end of the xed tubing I3 is sealed` in the head II by asuitable packer, or the like, so that the upper en d of the vannularspace or chamber I5 provided between the casing I 0 and the tubing I3 issealed off or closed. The tubing I3 extends downwardly into the iluid tobe pumped from the Well and at that point, which is near. the bottom ofthe Well, it carries the outer or xed elements of the gas control anddlsplacement units that we will hereinafter describe'.

In the ordinary /well -installation where well pumps are employed thedepths are not so great that shrinkage and. expansion or stretch of theprincipal elements involved cause any serious difculties, However, inthe case of very deep wells,

`for instancefunder operating conditions such as' Wewill hereinaftervrefer to, shrinkage and expansion, stretch and the pressures involved,generally,

. have a very marked iniluence upon the equipment or apparatus used. Invaccordance with our invention to'avoid difliculties due to conditionssuch as we have just referred to, we anchor the'parts at the bottom ofthe well that are required -to be stationary` or xed. We may in someinstances anchor those parts, forvinstance, parts of the control B, orofthe displacement unit, directly, as by anchoring them in the well casingor liner I0. However, in practice it is advantageous tovanchor or fixthe parts for practical purposes by an- /or 'annulus I1 leftbetweenthese elements, this being the space through which the actuating fluidor high pressure gas flows in passing from the head of the well to thecontrol B. f

In accordance with the arrangement that we have provided the ow stringextends from or through the actuating unitD down through the head II tothe gas control B where it carries the inner or working element of thegas control which element is in the nature of a plunger valve. Theflow'string I6 is in communication with the outlet of theunitA ythroughthe tubular inner elementor plunger valve ofthe gas control B,

, and it serves to conduct the uid from the well horliig the lower endportion of the outer tubng v In an ordinary well installation the lineron the lower endV of the well casing may extend several hundred feet upfrom the bottom of the well. In fact, it is not uncommon that it may bea thousand feet long, or more. We prefer to anchor the tubing I3 at apoint in the casing I0 proper rather than 'in the liner that may extenddown from the casing and, therefore, as we have shown in the drawings,we provide an anchor H for the lower end portion of the tubing I3 at lapoint well above its Aactual lower end and, preferably,

obstruct the passage of formation gas or exhaust gas through theIannulus I1 from the casing III tions. The slips and projections operateso that when the slips are set, -as shown in the drawings, downwardmovement or pressure on the tubing I 3 wedges the slips out intogripping engagement with the interior of the casing I0. The slips aresuitably connected to a tail piece or control mechanism 202 so that bysuitable manipulation they can be released for cooperation with theprojec, tions 200. In devices of this kind the control.l

mechanism 202 is usually such that the slips are held down or away fromthe projections 200 while the mechanism is being run into the casing Iand when the device has reached the desired point in the casing I0 thecontrol 232 is-released by manipulation of the stringbeing anchored torelease the slips so that they can be set.

With a securing device such as we have just described the lower endportion of the tubing I3 is suspended from the securing device, therebeing enough tubing I3 below the securing device to maintain the deviceproperly seated or [engaged in the casing I 0. The major portion of thetubing I3 or the length of the tubing I3 above'the securing device H maybe set so that it is held at the head II but hangs in the casing I0rather than being supported from the device H. In a practicalinstallation employing an anchoring or securing device H such as we havedescribed, there may be a substantial length of tubing I3 below thedevice H, but this will not be so long as to introduce any seriousdiiiiculties into the apparatus but rather will, for all intents andpurposes, besuch as to carry the stationary parts of the control B anddisplacement unit A so that they are practically rigid or stationary atthe desired location in the well.

In practice we prefer to employ a `simple, highly eiilcient form ofdisplacement unit `A and have found that a mechanism such as we haveshown in our Patent No. 2,318,029, issued May 4, 1943, is highlydesirable in carrying out our present invention. This particular type ofmechanism, being that illustrated in the drawings, involves, generally,a fixed body or barrel I8, a reciprocating tubular shell forming a flowtube I9 which oper` ates within the barrel I3 and through which thewell'iluid liasses to ow into the ow string I6., a foot or lower valve20 at'the lower end of the barrel I8, a working or upper valve 2| at theupper end of the now tube I3, a vent valve or valves 22 in the flow tubeimmediately below the 'upper valve 2l, and various other partsincidental lto I9 is attached to the lower end of the plunger or innerelement of the gas control B through the upper valve 2|, the saidelement of the control B being secured to the lower end of the flowstring I8. The tube I3 extends downwardly from the working valve 2| todivide the chamber 23 formed by the barrel I8 into an outer displacementchamber X and an inner displacement chamber and ilow passage Y.

The upper valve 2| acts as a working valve and may be an ordinary balltype valve such as is commonly employed in well pumps. Valve 2| isarranged to pass well fluid upwardly from the tube I9 into or throughthe inner element of the control B to enter and flo'w up through theflow string I8. In the particular form of construction illustrated thecage or body of the valve 2i serves as l a coupling joining the innerelement of the control B with the upper end of the tube I9.

The vent valve or valves 22 which we provide are check valves located atthe upper end' of the tube I9 and immediately below the upper valve Inthe drawings we have shown one valve 22 in the upper end portion of thetube I9 (see Figs. 6 and 13). Valve 22 connects the interior of the tubeI9, in other words. the inner chamber or flow passage Y, with thedisplacement chamber X around the tube I9, and acts to allow gas thatmay be trapped in or which may accumulate in the chamber Y to flow outof the chamber Y into the chamber X and out to the casing through gascontrol valves and exhaust ports 33, as well fluid flows into thepassage Y from its lower end during the filling cycle of the mechanism.

The gas control B, which is essentially a. valve mechanism, is locatedimmediately above the displacement unit A and serves as a coupling ormeans for. connecting the displacement unit with i the tubing I3 andflow string IIi.l The gas control is, preferably, a slide valve servingto control the flow of gas from annulus I1 to the chamber X during onecycle and to exhaust spent gas from the chamber X to the well externallyof the tlxed tubing AI3 during the other cycle, when the valve isclosed. In its preferred form the gas control involves two simple parts,an outer xed part in the form of a case or barrel 30, and an' inner re-(siilprocating part in the form of a core or plunger The barrel 30 ofthe gas control is an elongate l cylindrical member or element threadedat its cated in the bore 32 of the barrel 30. The plunger tion. In thepreferred arrangement we provide a suitable strainer 24, or the like,below the lower valve, and in practice we may employ any suitable deviceor attachment at this point as well l conditions may dictate.

The flow tube I3 is a reciprocating element and is operated by means ofthe reciprocating flow string I3.' In the preferred arrangement the tubeis threaded at its upper end for connection withl the lower lend of thedensity control section of the flow string IB'and is threaded at itslower end to receive or make connection withv the upper valve 2 I. Theexterior ofthe plunger 3l is turned and Vfinished to slidablyt the bore32 of the barrel an'd, in accordance with the preferred construction, anannular recess 34 is provided around the plunger at a point intermediateits ends, and a plurality of longitudinally disposedy ports 35 areprovided in the plunger joining the recess 34 with the upper end of thedisplacement chamber X of the 4displacement unit. The parts areyproportioned and related so that the. owI

that the recess 34 is in open communication with El v line I6 can beremoved carrying with it the plunger 3| and the tube I9 that normally'extends into the displacement chamber X.

When the flow string I6 is atthe lc w'er end of its stroke thetube ls is1n -its lowermost position and plunger 3| of the control B ls locatedentirely within the barrel 30. When the parts are in-this position thevrecess 34 of the plunger' is in communication with the exhaust ports 33of 4 the barrel so that gas remaining in the chamber X and any gasexpelled from the passage Y in the tube I9 through the vent valve orvalves 22 is free to escape up through the-ports 35 to the recess 34 andout through ports 33 into the well externally of the fixed tubing I3. Atthe same time fluid 'begins to' ilowinto the chamber 23 past the lowervalve 20. As the vilow string I6 I s elevated or moved upwardly theupper valve 2| remains closed and well fluids continue to iiow into thechamber 23, When the ow string reaches the upper end of its stroke, orwhen the gas control plunger 3| approaches the upper end of its stroke,the edge or Wall deilning the upper end of /tde recess'34 in the plunger3| passes -above or beyond the upper end of the bore 32 Aso the annulusII. By the time the parts reach the position just described the lowerend portion `of the plunger 3| covers the exhaust ports 33 so that highpressure gas from annulus I1 will not escape through the ports 33.

-Assoon as the recess 34 opens into communication with annulus I1 thereis a sudden change of pressures at or in the chamber 23 with the re-vsult that gas from annulus I1 immediately exerts into and out throughthe now string I 6.

In' accordance with our invention we provide meanswh'ereby the operatorcan easily establish 1 the proper cooperative relationship between the 1plunger 3I- and the barrel 30. From the foregoing -description it willbe apparent that the bar- .f rel 30 is, lfor practicalpurposes, ilxed orstation- 1 ary whereasv the plunger which cooperates with' the barrel iscarried onl the lower'end of the'ow string I6 which reciprocates'. Itwill be apparent that for proper action of the control which inl volvesthe barrel and plunger the'plunger must be operated or reciprocated inthe proper mannerrela'tive to the barrel and so that it is maintained inthe proper position relative to the barrel. Y

In practice the ow tube I3 of the displacement unit is -of considerablevlength and the barrel I8 which surrounds the ow tube to form thedisplacement chamber23 has to be of greater length so that it supportsthe lower valve 20 at a l point a safe distance below the lowermostpoint of travel of the ow tube I9 during normal operation of theapparatus, The means which we provide for positioning 'the plunger 3| inthe barrel l 30 involves'a stop 60 fixed in the barrel I8 at a point aknown distancev below the lower end of the flow tube when it is at thelower endof its l normal travel. For purpose of example, in practice wemay locate the flxeds-top 60, which is formed by crossed plates-fixed inthe barrel I3, a known distance, .say -for instance, five feet below thelower end of the tube I9 when the tube is at its lowermost point duringnormal operation of the apparatus.

Toset the plunger 3| in the properposition relative to the barrel theoperator lowers the entirereciprocating unit, that is, the operatingstring I6 with its connected parts, until the lower end of the tube I9strikes the fixed stop 60". He then knows that the plunger will beproperly positioned at the lower end of its stroke when theoperatingstring is lifted the said known distance,

namely ve feet.

The density control regulator C is provided immediately above -theplunger 3| #of control B.

Regulator C may be connected between the con-` the flow string I6 sothat the gas, in effect,

aerates the column of well fluid in the ilow string and lightens it bydisplacement. pressure gas enters the tube I6 it foams up and thusassists in including upward ow in the ow string. The regulator is apositively controlled element so-that it does not constantly bleed gasinto the iiow string but only admits gas to the flow -string I6 when thepressure vdiil'erential condition due to increased density of the bodyin the ow string I6 and annulus I'I is such as to.

make it desirable that gas-be flow string.

`In the preferred construction the density control regulator is aninsert applied to or inserted admitted to the vin a part such as thelower end portion ofthe string I6. In the form shown the regulatorincludes'a valvebody 40 with a vertically arranged opening entering theilow string I6 and having a.

proper operates within the body'4Il and includesl a stem 43 having ahead 44 to cooperate with the seat 4 I. A 'spring 45 is provided inconnection with the stem 43 so that it normally tends.

to open the valve. The spring 45 acts between a shoulder 45* inthe body40 and a plunger 45b on the lower end portion of the stem 43 to normallyyieldingly urge the stem down. The plunger 4lh operates in a bore 45provided in the body 40 and a port 45d connects the lower end portion ofthe -bore 45 with the annulus I'I so that the pressure prevailing in theannulus acts on the lower endof the plunger 45b and normally tends tomove the stem 43 upwardly. Ports 45x and 45' admit pressure from theflow string to the upper side of the plunger 45h. The opening-in thebody which carriesthe stem 43 opens up into they tube I6 at the upperend of body 40 and the seat 4I ispreferably an insertapplied to theupper end of the body opening.` i

The area of the upper end of the piston 45h .plus the area of the valvehead 44 at the seat 4I, when the valve is closed, equals the area of thelower end of the piston inthe bore 45. Pressure from the annulus I1 actson the lower side of the=-piston while pressure from the inside of Asthe highv -pressure acting on the lower end of the piston.

During operation the pressure in the flow line must be maintained sothat it is'less than that in the annulus, and the differential necessarydepends upon the length of the displacement chamber. AWe have foundthatinthe case .of

apparatus having a displacement chamber about 600 feet long it ispractical tol proportion the parts-of the unit just described so thatthe valve opens at a differential of about 300 pounds pressure pervsquare inch. Assuming operating conditions wherethe pressure in theflow string is below that in the annulus but the differential is lessthan 300 pounds, the valve remains open, but when the differentialincreases until it reaches about 300 pounds then the Vvalve closes. Whenthe valve opens gas from the annulus I1 entera` the string I6 tolightenthe body of material therein and'thus supplement the actiontending to now the uid up in the string I6.

It will be apparent from the foregoing description that the action ofthe density control regulator is entirely automatic.l Wherproperlydesigned and proportioned it opens `at a predetermined differentialbetween the pressure in the annulus and the load or weight within thestring I6 and effectively feeds gas into the string I6 to keep thecolumn of iluid'fiowing up and to keep the.l column of fluid mixture`light so that, in practice, a substantially uniform flow or dischargeof fluid is obtained at the upper end of the flow string I6, even thoughthe column is started up in impulses from the displacement unit.

If an attempt is made to initiate operation of the apparatuswhen-thevflow string I6 is full of fluid or has a substantial body oflfluid standing in it, the head pressure exerted by such fluid may' besufllcient to prevent operation. In accordance with our invention weprovide means for unloading the ow string I6 of excessive fluid to bringthe level of liquid in the tube I6 down to a point wherepressureconditions permit operation.V It is to be understood, of course,that when operation has once started and the density control regulatoris functioning in conjunction with the displacement unit the operationwill continue and this is true even thoughthe flow string I6 is full, asit must be for fluid toreach'the top of the well.

In the preferred vide one or more unloading valves G inthe string I6.vFor purpose of `example we will refer to a form of the invention whereone unloading valve is emplcyed. The 'unloading valve is located in thestring at or somewhat below the point in' the string at which liquid maybe standing without impairing initiation of operation of the apparatus.In any particular case the exact location of the unloading valve G willbe determined by the well conditions and the pressure factors involved.

In the form of construction illustrated the unloading valve ,G islocated ata suitable point in the tubing I6 which may be well above thelower end of the tubing I6 as indicated inthe diagram-l maticillustration, Fig. '1. In construction the unloading valve may be suchas we have shown in Fig'. 5. In this'illustration we show the unloadingvalve as including a body 50 arranged in the tubing I5. The body 50* hasa longitudinal opening 50b formed in it. The opening 14 I 501 is closedvat the upper -end of the body by a plug 50 and has a valve seat 5I)dthreaded into its lower end, the valveseat having a port 50 which' opensinto the interior of the tubing I6. The opening 50b in the' body hasanenlarged upper end portion 50. A valve seat 50! is formed where theenlargement of the body opening occurs. Ball valves 50h and lIi0icooperate with the seats I)d and 50i, respectively, and close down- 0w'ardly. The body 50l is held inthe tubing I6 by couplers 505. The`uppermost coupler 50! has a y -port 50'x through it which communicateswith the enlarged opening 50! in the body.

formv of the invention .we pro- `rWith the construction above describedthere vis a passage from the interior of the 'tubing I6 to the exteriorthereofthrough the port 50e of valve 50d, body opening 50h, enlargedbody opening 50', and the port 50k in the coupler 50. The valves 50h and50i are so located as to bein series in this fluid passage and tonormally seat downwardly. Under normal working conditions there 'is ahigher pressure at the exterior of the tubing I6.

than there is at the interior thereof, and therefore, the valves 50h and50l are normally closed or held on their seats and since they areinseries they supplement each other and positively Aclose the passagevagainst; leakage.

'When it is desired to unload the tube I6 of fluid down to the pointwhere the unloading valve G is located a high pressure is established inthe tubing I6 from its upper end or, in other words, a pressuredifferential is established between the linterior and exterior of thetubing I6 so that the pressure in the tubing I 6 is greater thanthatoutside the tubing I6, with the result that uid in the tubing I6will be discharged out through the unloading valve past the ball valvesof that unit into the annulus I1, or that is, into the.

e actuating mechanism D that we have pro-l vided is primarily a cylinderand piston mechanism mounted on the, landing flange and nipple above thehead II of the well. In its preferred o' form this mechanism includes,generally, a. supporting flange 41 and a cylinder 46 provided with alower head 41 and an upper head 48'. A piston rod'49 extends 'throughthe cylinder y46 and both heads of the cylinder and also flange 4'1, anda piston 50 is fixed on the rod 49 to operate in the cylinder 46.

In the preferred arrangement rods 5I are provided for tying the cylinderand heads together and for mounting the cylinder mechanism or unit onthe flange 41* which is supported on the landing flange I2. The rodshave threaded lower end portions 5I"l which' extend through openings inthe flange 41 and-they have plain upper end.`

v. is

49 is an elongate tubular member which pro-V jects out through the lowerhead 41 and ilange 41S intothe head Il of the well to connect .to

, the upper end of the flow string I6. The upper end portion of thepiston rod 49 extends up or out ythrough the head 46 and into thedelivery lin'e 55 which conducts the uid away from the well. l

Suitable packing means 56 is provided at the 'lower'. vhead 41 to packaround the piston rod `49 thel bwline includes a head 55* above thecylinder and lpiston unit above described to handle the upper endportion of the piston rod 49, a vertical section 55f oilset from andparallel with the cylinder and pistonmechanism, and a slip Joint in thevertical section 55) whereby the cylinder and piston mechanismcan be'bodily adjusted vertically, as above described, without disturbing theilow line. The head 55e is mounted ,a suitable distance above theycylinder head 48 vby means of spaced legs 60 which project upauassa A I.l

face equipment or more specifically from 4the ow string I6 which isdirectly connected with the plunger or movable element of the control.

'In carrying out our invention we can employ diilerent sources of power.In most instances it will be found practical to employ high pressure gasas the prime lmover for the entire apparatus vor system. We willdescribe a form of the inven-v ,i tion wherein a high pressure gas -isemployed as the prime mover.

The high pressure gas from any suitable source,

for example from one or more wells, or from a wardly from the cylinderhead. The head SI5l l has a packing means 55h which slidably passes theupper end portion of the piston rod,49 and it has an upwardly vextendingtubularv pro' 'l ec tion- 55 which surrounds the piston Arod, 49 and.which is closed at its upper end by 'a cap 55d.

The tubular extension 55 `of. the head 55*` is long enough or ofsumcient vertical extentto accommodate the piston rod throughout its`entiremovement or travel.

The 'head 55 delivers the flow received from the piston rod 49 to alateral flow connection 55 which joins to the upper end of vthe verticalsection 55l of the flow line.

The vertical section 55 of theilow line isar ranged parallel withthe.cylinder and piston mechanism adjacent one side thereof. The slipjoint provided in 'the vertical section of the flow line includes agland body 55'z secured to the ange 41 by a suitable mounting bracket55h and a follower 55l bolted tothe body`55 and operable to compresspacking 55|. The upper end portion of the vertical section ofthe flowline slidably enters the slip joint or, in 'other words, slidably passesthrough the `follower 55l Y, and through the packing 55! and projectsbelow or'beyond the body 552. 'I-'he lower part of the vertical sectionofi the ow line is xed or Joined permanently to the lower end of thebody 55 through a supply lin'e 1|.

and continues downward far yenough to accom- L modate the projecting endof the Aupper part of the said section of the ilow line'. The parts arearranged and proportioned so that the 'slip joint has sufllcientmovement to allow for full opera- -tion or adjustment of the cylinderand piston mechanism without disturbing the iiow line or, in otherwords, without requiring manipulation or setting of the flow line otherthan possibly adjustment of the packing gland of the slip joint.

The control system E for the lactuating unit includes, generally, apressure accumulatorA 6| and a lsystem of iluid connections and valveswhereby the actuating unit is controlled by or from the reciprocatingelement of the sub-,sur-

compressor plant, is supplied through a high pressure gas line 62. Aconnection which We will term a well branch 63 extends from the highvthe high pressure line 62 to the upper end of the accumulator 6|.

A normally closed inlet valve 65 is-.provided in the accumulator branch64. An exhaust line 66 connects with the accumulator branch 64 and isunder control of a normally open exhaust valve 61. The exhaust line 66may nally connect into the delivery line 55. To assure uniformityofoperation we prefer to provide a pressure regulating' valve 66 in theconnection which extends to the accumulator 6|, which valve 68 we locatein branch 64' between the'inlet valve 65 and the top of the accumulator.In practice we may employ an ordinary diaphragm controlled pressureregulator valve and the desired pressure can be maintained by providinga pressureA connectalternately charged and exhausted. A'timevconltrolled intermitter of any-suitable design is provided tocontrolthe pilot gas which operates the valves 65 and 61. Inl the preferredsystem pilot gas .is `supplied from a suitable source' We have shown thesupply of pilot gas taken from branch 64 ahead of valve 65 through apressure reducing valve 1|. Pilot -gas from the intermitter 16 acts onthe diaphragms of the valves 65 and 61through a line 10b with one branchconnected, to the diaphragm of valve 65 and another branch connected tothe diaphragm of valve 61. lThe intermitter 1l) maybe any suitable ycon-'trol device. For instance it may be a clock controlled mechanism whichlserves to admit pilot gas under pressure to the diaphragms o f theyvalves 65 and 61 at suitable time intervals. With the arrangementillustrated one of the valves is normally open and the other normallyclosed so that they operate oppositely. When gas is being admitted intothe accumulator to force liquid therefrom and into the actuator D thevalve 65 is-open while the valve 61 is closed, `but when it is desiredto,V exhaust'gas from the accumulator so that liquid can exhaust from"the actuator D,'then the valve 65 is closed and the valve 61 is opened.Valves 65 and 61 are disposed and coupled in the system so that when thecontrol or pilot pressure comes on valve 61 closes before valve 65opens, and .when pilot pressure is taken oil. then valve 65 closesbefore valve 61 opens. y

In practice we prefer to employ an intermitlet'valve closes and theexhaust' valve opens.

In Fig. 15 of the drawings we diagrammatically illustrate one form ofintermitter that can be used to advantage.

In the intermitter illustrated a slide valve coni trols flow from thepilot gas supply line 1| to the line b connecting to the diaphragms ofvalves 65 and 61. The slide valve involves a body |10 with an inlet port|1| at one side t'o which line 1| is connected, with an outlet port |12at the opposite side and to which the line 10b Vis connected, and withan exhaust port |13. The valve element |14 reciprocates in the body |10between a position Where it closes the exhaust port |13 and allowsconnection between the ports |1| and |12, and a position where' it cutsoff the anasse 1s 1 instead of being one above the other on the commonshaft |9|, are shown spaced apart and the shutters |93 and |95 are shownrelationship to the discs. l I

In the arrangement illustrated a plurality of stops |94 are adjustablearound a rim |96 provided on the disc |92 and they successively engageend operate the shutter as the disc revolves. When a vstop 94 engagesand operates the shutter |85 the shutter 1s moved to a. position toclose the nozzle |84 with the result that pressure develops in the righthand end of cylinder |15, causing movement of the piston |16 to theposivtion shown in the diagrammatic figure, so that pilot pressureenters the diaphragms of'valves 65 and 61 causing valve `65 to open andvalve 61 to close.

A plurality of stops |95 are provided on a rim |91 on disc |93 andsuccessively engage the shutter |83 to operate it. When shutter |83 ismoved by a stop |95 to close the nozzle |82 pressure builds up in thelefthand end of the cylinder |15 causport |1| and opens port |12 to port|19. When the valve is in the rst mentioned position pilot 4gas pressureis admitted tothe diaphragms ofl valves 65 and 61, whereas when it is inthe second or other position pilot gas is exhausted 'from thediaphragrns of valves 65 and 81.

The intermitter 10 involves means for reciprocating the valve |14between` the .two positions above described. Such means may include anoperating cylinder and piston mechanism for the valve |14. In thedrawings we show a cylinder |15 at one end of the valve body |10 and a`piston |16 operating in the cylinder |15 and carried on an extension ofthe valve |14. With this arrangement when fluid under pressure isadmitted to either end -of the cylinder while the other end is open, thepiston will move toward the saidother end of the cylinder.

To alternately admit .and exhaust pilot gas to the cylinder |15 toreciprocate the piston `|16 therein, we providea pilot gas line |80 fromthe pilot gas supplyk 1| to one end of the cylinder |15 and a pilot gassupply line |8| 'from the pilot gas' supply 1| to the other end of thecylinder |15. An escape nozzle |82 isprovided in line |80 adapted to beclosed 'by a pivoted shutter |83, and an escape nozzle |84 is providedin line |8| adapted to be closed by a pivoted shutter |85.

From the foregoingA description it will be ap parent that when thenozzles |82 and |84 are open pilot gas escapes so that no pressurebuilds up in the ends of the cylinder |15 but if either one of thenozzles vis closed by its shutter, pressure will develop in the line inwhich .the nozzle is connected, and consequently pressure will developin the corresponding Vend of the cylinder |15. 'l

With this mechanism the desired action or operation oi the piston |16 incylinderr |1'5 can be I. gained by operatingthe shutters |83 and |85 atproper intervals vand in proper sequence.

Various means may be provided to operate the shutters.` For example, as,indicated in the drawings, a spring motor,'or the like, |90may beprovided to drive ashaft |9| so that it turns constantly. Control discs|92 and `|93 maybe provided on the shaft, |9| to carry stops |94 and|95, respectively, to operate the shutters. In the diagram, Fig'.15,-the discs |92 and |93,

ing the piston |16 to move to the righthand end of cylinder |15 and thevalve |14 to operate to der |15 there must be no pressure developed in.the other end of the cylinder, otherwise the piston |16 would not move.lIn practice the two discs |92 and |93 are, as we have said, ,on thecommon shaft |9|, and there is an equal number of stops on each disc.The discs are individually adjustable aroundthe shaft |9| and they areset in relative rotative positions so that the stops 94 and 95 operatethe shutters successively. For example, if it is desired that there befour complete cycles oi' operation for each revolution of the shaft |9|,then we provide four stops |94 on the disc |92,v

andwe provide four stops |95 on the disc |93, and we arrange the twodiscs in different rotative positions so that as the shaft |9| turns theshutter will be operated and then, 'at a predetermined intervalthereafter the shutter |83 will be operated. Following this cycle ofoperation the next succeeding stop |94 will come into position'and theshutter |95 will be operated for the second time, and following this, atthe'desired interval, the shutter |83 will be operated for the secondtime, land this sequence continuously repeats itself so long as theshaft |9|' rotates.

In the particular mechanism illustrated the stops |94 and |95 operatethe shutters through spring arms |98 on the shutters, which armsj makeit unnecessary to provide a very line adjustment of the parts. Thevarious parts are related and proportioned so' that the shutters areonly momentarily operated, that is, theyare notA held closed, with theresult that when the piston |16has been moved to either end of itsstroke thepressure that operated it is released and the4 mechanism isready for the next operation as soon as a shutter is operatedby one ofthe stops. In other Words the system is such that the pilot pressure isnormally exhausted from the two ends of thecylinder |15 and positivepressure is developedin the cylinder only long enough to move the piston16 from one end to .the other, depending upon which-shutter is operated.

From the foregoing description it will beapparent that the intermitter10 is in realityA the in proper I guasto' ,the 'gas' control valvellocate-d down inl the well is operated. The. intermitter accomplishesthis control through 'the valves 55 and 61 which, in turn, controll themovement of the cylinder and piston mechanism that lifts the ow string,which .in reality is a 4valve stem for the movable valve' element of thegas control valve in the well. By-

providing for simple accurate. adjustment of the" intermitter, as abovedescribed, we are able. to convenientlyand accurately adjust lthe actionof thewell parts.` l

The-period of'rest gained at the upper end or topv of the stroke throughproper setting of the u intermitter may be,"an'd preferably is, such asto allow su'iiicient time for vfull emptying of the disout excess timedelay we gain maximum operating eiiiciency. It is. to be noted that the,in-

ler1' communication between thesupplyjeonnec tion 95 andthe pilotpip'e`85.

An extension IIlI ofthe valve member proper," f. projects from one endofthe bodyf`9| so that'it canV be operated tomovethevalve against .the``spring 99 to a position where the large head 96 is away from the seat 94establishing connection bey tween the supply connection 95an'd thepipe85, 4 before which time the small head has moved to:` a `position whereitcovers an exhaust port IUI which is normally open. f

The general relationship ofthe parts thus far described is such thatwhen the valve of the pilot u l '.'valve 98 is operated againstv theactionfofv the l* placement chamber, and likewise, the' period of u irest gained at the lower-end or bottom of the stroke by proper settingof the intermitter may be, and preferably is such as to allow complete.v filling of the displacement chamber from the well. By' setting theintermitter soy that the l periods of rest allow complete emptying andcom'- y plete lling of the displacement chamber withtermitter is locatedat the surface of the well I and it is through this Vunit of surfaceequipment 1 that we are able" to vary the periods of rest at f the topand bottom of the. stroke to initially gainproper setting, and vto varythe setting from ltime to time as well' conditions may change; It shouldbe vfurther noted that we can vary either n time period, that is, eitherthe periodvof rest at..

t the top of the stroke, or the period of rest at l the bottom of thestroke, or both, and can do this without in any way alterating ormanipulating the equipment in the well.

In accordance with our invention we provide a tbody of L 'quid L to4 behandled by the accumulator and to.be conducted to the means D to operateit. A suitable conduit-88 is provided connecting thel lower end of theaccumulator'with the. lower end of the cylinder of the means D.

i We provide a control valve 8| in the connection I 88 and a by-pass 82around the valve 8l. The

spring 99 the valve 8| is closed so thatuid under.-

pressure from the accumulator Ais cut off from entering the cylinder ofthe means` D.l

To effect operation of the pilotlvalve'90 at the desired point duringoperation of the displace ment unit and control in the well we providean operating connection between the reciprocating element of the controlB and the pilot-valve 90. Since the Working elements of the displacementunit'A and of the gas control B are'directly linked to the flow' stringI6 and the flow string is coupled to the piston 49 of the means D wetakethe operating movement from the piston rod 49'.' Y

, In the preferred arrangement weprovide an A adjustable collar |.I0 onthe piston rod 49, and.

We provide a hinged lever or trigger I II .to actu-v ate the extensionIlllfofA the valve 98. The valve 90 kis supported by mounting bracketI|3 so that it isat the upper side of the upper head 48 and the triggerI I I which engages the valve extension IBI lis pivotally mountedon/abracket arm -IIIa located adjacent to or in the vicinity of thepiston .iv

rod 49 as it passes in the zone between the head 48 and the deliverypipe 55. The collar-H0 is fixed on the piston rod 49 to pass freely'through an enlarged opening I|5 in the head 48 and is proportioned sothat it will -engage and operate i 1 the trigger I I I. `In practice itis desirable to adby-pass is provided with a check valve 83 arl rangedto allow free ow only from the means D to they accumulator past thevalve 8h The valve 8| is a normally open motor valve l. preferablydesigned to be operated by pilot gas supplied through a gas connection85 which is joined to the diaphragm or power elementof thel valve 8|. Inaccordance with vour inven- 'tion a three-way pilot valve 90 controlsthe sup- 1 ply and exhaust of pilot gas to and from the gas 'iconnection 85 so 4that it controls the actionvof the valve 8I-. f

The pilot 'vaive 'sojsiown in Fig. 3 is preferably a simple slide valveincluding a cylindrical l 1 body `9| having a large bore i92 at oneiendand j a small bore 93 at the other end'whichbores join to form: a seat94. A pilot ga's'. supply connection l 95 is connected into the large.bore 92 and the 1 pilot gasline 85-connectsintothe inner end portion ofthe small' bore I93. An exhaust4 port |Il|a "connectsinto the outer endportion of the small bore.L

A valve element operates in the body 9| and 1has alarge head 96operating in the large bore.

92 and a small head' 91 operating -in the small bore 93.V A stem 98connects'the heads 96 and 91.

mally urgesrthe'valve to a position where ythe -:large head 92l engagesthe seat 94 thus closing just or regulate the position of theactuatingcollar ||0 along the piston rod 49 and, therefore, we split'the collarso it is in two sections which assemble around the piston rod.- The twosections of the colar' are held in tight gripping engagement with therod by means of annular coiled In operating or during operation of themechaniism thatv we have thus far described,4 assuming that the flowtube of the displacement'unit is at the lower -end of its stroke, orthat the flow string.

IB is down, the intermitter 19 (Fig. 1.) operates to close valve 61 andopen valve 65 with the result that high pressure gas from the lline 62enters the top or upper end of the accumulator 6| exerting high pressureon the liquid L in the accumulator.

to the chamber Xvof the displacement unit A,' whereuponA there' will bea ,tendency for the upward movement of the flow string toaccelerate.

"A spring'99 carriedin'a suitable cage |88 nor-v' dueto thepressureacting under plunger 3| in'- mechanically stopjthis acceleration of theflow main inactive. However, s

21 string weA use thisvmovement or this portion of the movement of theiiow string to bring the collar H" into cooperativeengagement with thetrigger III so that the three-way pilot valve 90 is then operated., Itshould be noted that the construction of the control B in the well issuch as to allow for considerable overtravel after the control hasopened to allow high pressure gas to l enter the displacement unit A. Itis' during this overtravel that the pilot valve is .operated tocause l0gradual termination of the upward movement of flow string I6.

As soon as the three-way pilot valve'90 is opj erated by the collar H0the valve 8| starts to close so that flow of operating iiuid to thecylinder of the means D is cut down and iinally cut of! completely. Thepressure used in the pilot system and the size and length-of the pipeshandling pilot gas are related to the diaphragm control of the valve 8|so that it takes some little 20 time', `say a fraction of a second,after valve 90 is operated before'the valve 8| is actually closed and,therefore, the 4tubing comes. to rest gradually or slowly, andl thusprevents jarring of the parts. The intermitter 10 is set so'thatfollowing clos- 25 ing of valve 8| there is a time interval when piston50 remains in its up position to allow the displacement chamber in thewell to empty after which valve 65 closes and valve 81 opens,l so gasexhausts from the accumulator through the connection 66 tothe owline 55.When this occurs the uid under the piston 5|) in the means D is free toescape through the connection 80 and the by-pass 82 and check valve 83so that it returns into the accumulator. Itis to be noted that theweight of the flow string will put pres'- sure on the liquid under thepiston to exhaust it from the cylinder of means D back into theaccumulator B l.

Thrifugh v.the interconnection of the rgas con- 40 trol B at thedisplacement unit A and the control means E through the pilot valvel 90of 'the control means We eiect a highly efficient and satisfactoryoperation. There is no damage vor difficulty resulting from the surge oracceleration which occurs when the high pressure gas is suddenlyadmitted to the pump, and the entire system operates smoothlyandautomatically without the excessive use of gas and without requiringconstant or careful supervision.

' From the foregoing description it will be apparent that theaccumulator 6I handles a bodyA of operating uid, as for instance, oil orthelike, which body of liquid is held inthe bottom of the` accumulatorwhile high pressure gas is introduced into the top of the accumulator't'o exert pressure on the liquid. It will be understood that shouldleakage occur in the system so that the 'liquid normally handled by theaccumulator is dissipated or lo'st, the high pressure .gas might findits 60 way from the accumulatorto the means D and cause erratic orunsuitable operation of the means D. To eliminate the possibility of gasever reaching the means D we provide a liquid level control means inconnection with the accumulator. We may provide a stop valve 250 in theline'80 at the accumulator under control of a float control means 23I Inthe drawings We have shown a stop valve 250 which is normally open andwe show a typical float control device 23| connected '.770 into thelower portion of the accumulator and joined to the valve 250 by suitablelinkage 252. These parts normally have no influence on the i operationof the apparatus but` rather they rehouid the levei of nquid in the.accumulator fall below a predetermined` point the float control 231 willoperate. and

through the linkage 252 will operate the stop valve 250 so that the lineis cut off, separating the accumulator from the means D.

In accordance with our invention we provide means to check downwardmovement of the piston 50 in cylinder 5I :as it reaches the lower end ofits stroke, in order to prevent a hammer or Jar such as would otherwiseoccur if the piston were allowed to be stopped solely by the cylinderhead 181.` In the preferredV arrangement we provide an annular cup 41xvon.the inner side of the lower cylinder head 41 concentric with thepiston rod 49 and we provide the cup with a finished bore I1?. Adownwardly extending projection MY is provided on the lower side ofpiston y5l) and this,

. projection has its exterior' Illl" turned to slid,

ably t into the bore 411. As the piston 50 approaches theglower end ofits stroke the projectionr4ly enters the cup 411x and the fit betweenthe projection and cup is such as to allow the 'actuating iiuid trappedin the cup to gradually escape. The mechanism acts as a hydrauliccheckor stop that effectively prevents hammering or sudden shock whenthepiston reaches the lower end of its stroke.

From the foregoing description it will be apparent that we have providedapparatus for lifting fluid from a well through the use o'f asystem orarrangement that is closed from the well, that is, the only opening orconnection provided between the well, or interior of the well casing I0,and the apparatus that we have provided is through the bottom end 4ofbarrel I8 past the bottom valve 20 and since the bottom valve 20 is, ineffect, a check valve positively preventing flow out through the bottomof the barrel I8, the apparatus that we have provided is closedso thatwe never `create appreciable pressure on the well or the well formation.The vamount of gas exhausted into the well through the control B is, inpractice, negligible. The absence of back pressure is a highly importantfactor in that for effective handling of well fluids with `apparatussuch as we have providedl the actuating medium, forinstance-the gasemployed in the annulus I1, is necessarily under high. pressure and ifsuch pressure is allowed to come upon the well or the 1well formation itmay, and in fact in practically all cases it would materially retard, ifnot kill,

the Well. By providing a closed system and by I thus keeping pressureoff the well we remove the well uid and at the sametime create acondition in the well which actually inducesy higher production from thewell, l

By having provided apparatus which forms a closedsystem and through theparticular arrangement which characterizes our invention, the highpressure actuating gas in the annulus I1 flowsdownv through thecontrol'B and in -thus flowing, and if there is any leakage through thecontrol, that is between'the plunger and its barrel, these parts areswept clean so that they may actually: operate dry. It is apparent thatvthese f parts must handle or control high pressures and consequentlywill operate lmore eiiciently and without, danger of fouling 'orbecoming injured ifY they arenot dry but, rather, are lubricated.

In accordance with our --presentinvention we provide lubrication for theworking parts of the control B. We dothis -by introducing a'suitablelubricant into the annulus I1 through thejhead Il. In accordance withthe' preferred form of the invention a suitable amount of lubricant isapparatus. i

fed to the Iannulus I1 as the apparatus operates and to assure theproper feed of lubricant, that is, to assure thefeed of lubricant whenthe apparatus operates, and a quantity of lubricant proportionate to theoperation of the apparatus, we coordinate the lubrication with theaction of the In .the form of the sure regulator 302, 'I'he pump drawslubricant invention illustrated wev provide a lubricant pump 300 drivenby a gas motor 30| supplied from line 63 through a pres' with the pumpediiuid through the delivery pipe from a suitabiesupply reservoir 303 anddelivers v it to the head vII to enter the annulus I1. 'Ihe i lubricantpump can be operated by the gas pressure or from .the reciprocatingelement o f the apparatus, for instance, it may be' connected to thepiston rod I9 so that itis operated each time l the piston rodactsfthrough its cycle of operation.4

The lubricant delivered in suitable quantity and at suitableintervals tothe annulus I1 falls The lubricant Vthus deposited working parts of thecontrol B and in practice practically all of it nds its way through thecontrol VB. either between the working parts or with the operating gas,so that it is deposited with l thewell fluid in the chamber 23v and iscarried'- I vout of the well through the action hereinabove described.

, In order that it maybe fully appreciated that we have by our inventionprovided a combination of elements that will accomplish results'notobtainable with ordinary so-called gas lifts, we 1 would explain thatour mechanism will work efflciently when taking well uid from a well ata .depth of approximately eight thousand feet, or more.l In suchapplication of the invention the initial actuating pressure, that is,the pressure i at which the actuating gas is introduced into the head IIto enter the annulus I1 may be approximately 1200 pounds per squareinch. There maybe a pressure dropof about 150 pounds per squarev inch inthe'annulus vfrom the top of the well to the point where the control Badmits the gas to the, displacement unit so that there is a disl bygravity* down through thev annulus and is finally deposited at the upperend of the control V B, that is, at the point where the high pressuregas enters the control for admittance lto the displacement unit. findsits way or is forced between the relatively gas funder pressureincluding, a stationary tubing` placing pressure'of about 1050 poundsper square inch applied to the =uid in the displacement unit.

can .be usedfrom the time that a. Well requires an artiiicial'lift untilit is ready'for abandon-l ment.' n

It should be noted that the'gas employed exhausts through the ports 33into the space between the tubing I3'and thewell casing I0 so that itcan be bled or takenfrom the head I I through i a suitable bleederconnection |20 which, in turn, 3 connects into the delivery pipe 55through a pressure regulating valve |20?- s'o that there is no wastewhateverv offgas.` When the various parts iar'e thus connected the gasused in displacing liiuidat the displacement unit A is led to the de'-livery line, the gas lpassed into. the ow string by the densitycontrolgregulatorl C and the gas'used f in the accumulatorA all ows tothe delivery line From the foregoing description it will be ap-V lparent that we have provided a uid lifting apparatus which is subject toconsiderable variation making it practical for use under a wide I rangelof well conditions. In practice the apparatus that We havev provided isso flexible that it so that it is notlwasted andso that thesystem isentirely enclosed.` As a result of the hookx up .that we have providedthe high pressure gas entering the apparatus through the connection 82performs the various functions we have described and then finallydischarges from the apparatus Having describedVonly a typical preferredform and application of our invention, we do not wishto be limited orrestricted to the specic details herein set forth, butwish to reserve toourselves any variations or modifications that may appear to thoseskilled in the art and -fall withinl the scope of the following claims:I

Having described our invention, we claim:

1. Apparatus for lifting fluid from a wel1,by

gas under pressure including, a stationary tubing extending into thewell and receiving' gas vunder pressure at its'upper end, a, tubularflow the flow line, and a control for said actuator opy erable to ladmitoperating uid under pressure tothe cylinder to movethe piston' so thatthe line is moved upwardly and including means controlled by the saidline stopping ow of said .uidto the cylinder to stop upward movement of`the line. l

2. Apparatusfor lifting iiuid from a well by extending into the well`and receiving gasV under pressure--at its upper end, a tubular ow lineextending into the well through the tubing and adapted to bereciprocated, a displacement unit carried in the Well from said tubingand line and including a stationary barrel forming a displace? mentchamber, a dow tube to be reciprocated in the barret' and valvescontrolling now of well iiuidthrough the chamber, a gas controlat theunit operable by reciprocati'on of theiiow line to admit 'gas' from thetubing to the vunit to displace well uid /from the unit into-the iiowline when the said lineapproaches the upper end of its stroke and to.exhaust gas from the unit following displacement ofy well iiuidtherefrom including a tubular valve barrel forming- -a connectionbetween thetubing and the rst mentioned barrel and a valve plungerforming a .coupler and fluid connection between the flow line and pingflow of said fluid to the cylinder to stop flow tube and slidablyoperating -in the said-valve barrel, a cylinder and piston actuator atthe top of the well for lifting the flow line, 'anda control 'for .saidactuator operable tol admit loperating -uid under'pressure to thecylinder to move the piston so that the line `is vmoved upwardly andincluding means controlled by the Asaid line stopupward movement of theline.

- 3. Apparatus for pumping a well by gas under pressure including, afixed tubing extending into the well and receiving gas-under pressure atits upper`end,- a tubularnow line extending into thei lwell through -thetubing and adapted to bereciprocated a pump lcarried in the well fromsaid tubing and line, a gas control at the pump op erable byreciprocation or the flow line to admit fluid from the pump into theilow line and to exhaust gas from the pump following displacement ofwell fluid therefrom, one or more adjustable density control regulatorsspaced along the flow line to admit gas from the annulus into the flowline to facilitate ilo'w of well fluids upward through the' flow line, a`cylinder and piston actuator at the top of the well for reciprocatingthe flow line, and a control for said actuator operable to admitoperating liquid under pressure to the cylinder to move the piston sothe line is moved upwardly and including means controlled by the saidline stopping flow ofA said fluid to the'cylinder to stop upwardmovement of the line.

4. Apparatus for lifting fluid from a` well by pressure fluid including,a stationary tubing extending into the well `and receiving fluid underpressure at its upper end, a tubular flow line extending into the wellthrough the tubing and adapted to be reciprocated, a displacement unitcarried in the well from said tubing' and-line; at

fluid control at the unit operable by reciprocation of the flowrline'toadmit fluid fromthe tubingto the -unit to displace'well fluid from theunit into the flow line and to exhaust fluid from the pump into the wellaround the tubing following displacement of well fluid therefrom,adelivery line receiving well fluid from the flow'line at the top of thewell, a connection between the well around the tubing and the deliveryline-so that fluid from the well enters thedelivery line,

Aa cylinder and piston actuator at the-top of the well for Alifting the`flow line, and a. control forsaid actuator operable "toadmit operatingfluid" under pressure to the cylinder to movelthe piston so that theline is moved upwardly and including means controlled by 'the said linefor Astopping flow of saidfluid to the cylinder to ward movement of theline.

5. Apparatus for handling well fluid bygas under pressure including, astationary tubing ex-A tending into the -well and receiving gas underpressure at its upper end, a tubular flow line extending into the wellthrough the tubing and adapted to be reciprocated, a vdisplacement unitcarried in the Wellfrom said tubing and line, a

gas control at the unit operable by reciprocation l of thegflow line toadmit gas from the tubing to the unit to displace well fluid from theunit into the flow line when the said line approaches the upper end ofits stroke and to exhaust `gas from the yunit into the well `around thetubing' following 'displacement ofl well fluid therefrpm, a deliveryline receivingwell fluid from the flow line at the top of the well, aconnection between the well around the tubing and the delivery line sogas from the well enters the delivery line, a density control regulatorin the flow line adjacent the unit to admit gas from the'tubing intostop upthe flow line when av predetermined pressure differential existsbetween the flow lineand tubing to facilitate flow of well fluids upwardthrough the flow line, a cylinder 4and lpiston actuator at the top ofthe well for lifting the flow line,anda control for said actuatoroperable to admit operating fluid under pressure to the cylinder to movethe piston. so the line is'moved upwardly and including means controlledby the said line stopping flow of said fluid to the cylinder to stopupward movement of the line.

6. Apparatus for handling wfellviluid by lgas,

under Apressure including,v a stationary `tubing extending intothe welland receivinggas under y pressure at its upper end, a tubular flow lineex` tending into the well through the tubing and gas control at theunitoperable by. reciprocation of the flow line to admit gas from'thetubing to the unit to displace well fluid from the unit into the flowline when the said line'approaches the upper end of its stroke andto'exhaust gas from the unit following displacement of welll fluidtherefrom, a cylinder and piston actuator at the top of the well forlifting the flow line, and a control for said actuator operable to admitoperating liquid under pressureto the cylinder to move the piston so theline is moved upwardly including an accumulator handling said liquid andholding gas to exert pressure on the liquid, an inlet valve controllinggas flow to the accumulator, an exhaustv valve controlling exhaust ofgas from the v accumulator, an intermitter controlling the inlet.

and exhaust valvesto alternately open and `close them, a liquid handlingconnection between the accumulator and cylinderra control valve in saidconnection, and means controlling the' control valve from the flow lineso the control valve 'closes following operation of the gas control toadmit gas to the pump.

y7. Apparatus for handling well fluid by gas ,the unit followingdisplacement lof well fluid therefrom, a cylinder and piston actuatoriat the top of the well for lifting the flow line, and a control forsaid actuator operable to admit operating liquid under pressure to thecylinder to move theV piston so theline is moved upwardly lincluding anaccumulator handling said liquid and holding gas to exert pressure onthe liquid, an inlet` valve controlling flow of gas to the laccumulator,an exhaust valve controlling exhaust of gas from the accumulator, anintermitter controlling the inlet and exhaust valves to alternately openand close ther/n, a liquid handling connection between thel accumulatorand cylinder, a control valve in said connection, a bypass in' theconnection around the control valve allowing flow only from thecylinder, and means controlling the control valve fromthe flow line sothe control valve closes the following operation of the gas control toadmit' gas to the unit.

8. Apparatus for handling well Afluid by gas under pressure including, ailxedtubing extending into the well and receiving lgas under pressure atitsA upper end, a tubularV flow line extending into the well through thetubing and adapted to be reciprocated, a unit'carried inl the well fromsaid tubing and line, `a gas control at the unit operable byreciprocation of the flow line to admit gasfrom the tubing to the pumpto displace well fluid from the unit, into the flow line when' the saidline approaches the upper end of its stroke and to exhaust'gas from theunit following displacement of well fluid therefrom, a cylinder andpiston actuator at the top of the well for lifting the `flow line, and acontrol for saidactuator operable to admit operating liquid underpressure to the cylinder to move the' piston so the line is moved wiru-pwadly and including means controlled by the ,I

said line stopping flow of said liquid to the vcyl-` inder to stopupward movement o\the line, the said meansincluding a valve with acontrol part i j and a member moved with the flow line to engage andoperate the control part. y

9. Apparatus for handling well iluid by gas under pressure including, astationary tubing ex' tending into the well and receiving gas underpressure at its upper end, a tubular ilow line extending into the wellthrough the tubing and adapted to be reciprocated, a displacement unitcarried in the well from said tubing and line, a gas control at the unitoperable by reciprocation of the ow line to admit gas from the tubing tothe unit to displace well fluid` fromthe unit into the flow line whenthe said line approaches the upper end of its stroke and to exhaust gasfrom' the unit 't following displacement of well iuid therefrom, a

cylinder and piston actuator at the top of the well for lifting the ilowline, and a control for said actuator operable to admit operating liquidunder .pressure to the cylinder to move vthe piston so the line is movedupwardly includingV a control valve controlling'iiow of liquid to thecylinder, a pilot valvefcontrolling the control valve, and an operatingelement onl the ow line cooperating Y with the pilot valve.

' 10. Apparatus for handling a well uid by gas under pressure including,a stationarytubing exsaid actuatcroperable to admit operating liquidunder pressure to the Acylinder to move the piston lso the line ismovedupwardly including a control a pilot valh e controlling the controlvalve, and an operat g element on ing with the pilot valve. e

-12. Apparatus for handling well fluid by gas valve con'nlling flow ofliquid to the cylinde'r,

' under pressure including, a fixed tubing extend'-y r to bereciprocated, a displacement unit carriedin the well from saidtubing'and line, la gas contending into the well and receiving gas underpressure at its upper end, a tubular flow line extending into the wellthrough the tubing and adapted to be reciprocated, a. displacement unitcarried inthe well fromsaid tubing and line, a gas control at the unitoperable by reciprocation ofthe flow line to admit gas from the tubingto the unit to displace well lHuid lfrom the unit into the ilow linewhen the said line approaches the upper end of its stroke and. toexhaust gas vfrom the unit following displacement of well iluidtherefrom, a cylinder and piston' actuator at the top of the well forlimiting the rlow'line, and a.A control for said actuator operable toadmit operating liquid under pressure to the cylinder to move zthepiston so' the line is movedupwardly including a control valvecontrolling flow of liquid to the cylinder, la pilot valve at theactuator controlling the control valve, and an operating' element on theflow line cooperating with the pilot valve.

, 11. Apparatus for handling .well uid by gas under pressurev including,a stationary tubing ex- -tending into the well andV receiving gasunderpressure at its upperend, a tubular ilow line extending into the wellthrough the tubing andv adapted to be reciprocated, a vdisplacement unitcarried in the well from said tubing and line and including a stationarybarrel forming a displacement chamber, a ilow tube to-be reciprocated inthe barrel and valves controlling ow of well iluid through the chamber,a gas'control at the unit operable by reciprocation of the flow line toadmit gas from the tubing to the pump rto disp'lace well uid from theunit into thev flow line when the said line approaches the upper end ofits stroke'and to exhaust gas from 'the unit following displacement ofwell uid therefrom including a tubular valve barrell torming'aconnection between theV tubingl and barrel of the unit andavalve'plunger forming a coupler and uid connection between the ilow lineand ilow tube and slidably A`operating inthe valve barrel, la cylir arand piston actuator at the top oi the well rlifting the iiow line, and acontrol for.

ing into the well andreceiving gas under pres-v v sure at its upperend,a tubular iiow hne extending into the well through the tubing andadapted cluding an accumulator handling said liquid and ladapted toreceive high pressure gas from a sup- 'Ply line, an inlet valvecontrolling the admission of high pressure gas to the accumulator, anex` haustl valve controlling the exhaust of gas from the accumulator, aliquid connection between the cylinder and accumulator, a control valvein said' connection, anda pilot valve operated by the ilow linecontrolling operation of the control valve.

13., Apparatus for handlingwell uid by gas under pressure including, astationary tubing extending into the well and receiving gas underpressure at itsupper end, a tubular iiow line ex-v tending into the wellthrough the tubing and v adapted to be reciprocated, a displacement unitcarried in the well from said tubing and line, a gas control at the unitoperable by reciprocation of the flowline to admit gas fromthe tubing',to

the unit to displace well fluid from the unit into the ilow line whenthe said line approaches the upper end of itsstroke and to exhaust -gasfrom the unit following displacement of well vfluid therefrom, acylinder and piston actuator at the ,Itop of the well for lifting the owline, 'and a control for sai actuator operable to admit loperatingliquid derypressure to the cylinder to ,move the pist A Aso the line ismoved upwardly includin an cumulator handling said liquid and Vada tedto receive high pressure gas from a suplly line, an inlet valvecontrolling the -ad. mission of high pressure gas to the accumulator, anexhaust valve controlling the exhaust of gas from the accumulator, aliquid connection between the cylinder and accumulator, a control valvein-such connection, a bypass around the control valve so the weight ofthe ow linevdis# places liquid from the cylinder to the accumu-l latorwhen the control valve is closed and the exhaust valve is open, 'andapilot valve operated by the flow line controlling operation of thecontrol valve.

14. Apparatus` for handling. well fluid b'y gas 'under pressureincluding, a stationary tubing ex' l tending into the well-andreceiving, gas 'under pressure at its upper end, a tubular ilow lineextending into the well through the tubing andadapted'to bereciprocated,a displacement unit carried `in the well from said tubing and line, a,

gas control at the unit operable by reciprocation of the iiow line to'admit gas' from the tubing to the ow line cooperatl

